You are here

2016-09-05 Petcock, Gas Tank Vent


2016-09-05 Petcock, Gas Tank Vent

Had issues with the tank pressurizing when hot with fuel escaping past the pet cock and into the crankcase. Ack.

The cap innards. Be sure to not lose the springs.

I have to mark things.. or else spend wayh too much time figuring out how it should go back together..

The latching side.

The cap is venting correctly. The path is from the red circle to the smaller red circle between the two screws. No problem here.

Onto the tank. The middle hole is the vent hole. I pressurized this hole and got good flow through the tube that sticks out from the back of the tank. Should have taken a pix of it but you know where it is.. So the tank is not the problem either.

Reassembled, using light grease.

This petcock is toast. Thanks to my buds at, learned that a 1980's GPZ900 uses the same physical configuration but has a vacuum operated petcock. When vacuum is present, valve is open. No vacuum, valve is shut. It also has 'prime' position which I assume is 'straight-through' flow. Clicky

Added a washer under the screw to lift the scew slightly from the channel it rides in. When hot, the petcock is damn near impossible to move by hand.

Yes, this gasket is hot. I have a new one but want to save it for the new petcock.

The end.


Theme by Danetsoft and Danang Probo Sayekti inspired by Maksimer